One last Christmas gift project for my sisters and brother-in-laws were passport covers. I found the tutorial at BunnyBum and whipped up 8 of them pretty quickly (the first was a practice "throw-away"). I lined a few of them with contrasting colors before it dawned on me that when in use the inside would never be seen. After that I just used the same fabric.
This was an extremely easy project, and for the travelers in your life it might be a good way to distinguish passports quickly. It's also a great way to use up leftover fabric scraps.